Re: [PATCH v6 4/5] perf script: Add --lazy-load-symbols to load symbol names lazily

[sashiko-bot@kernel.org]

> From: Alireza Haghdoost <haghdoost@uber.com>
> 
> This patch adds the --lazy-load-symbols option to perf script. With this
> option, perf reads the name of a userspace ELF symbol only when a lookup
> returns the symbol. Eager loading remains the default.
> 
> perf script loads the ELF symbol table of every DSO that appears in a
> sample and keeps each symbol, with its demangled name, until exit. Most
> of those symbols are never sampled, and their names take most of the
> memory. On a large profile this makes symbol loading the main memory
> cost of perf script, and in a memory-constrained cgroup an OOM kill.
> 
> With the option, the loader still creates every symbol, so end fixup,
> duplicate selection, PLT synthesis and IFUNC marking work as before. But
> it keeps the file offset of each name instead of copying and demangling
> [ ... ]
> C++ service, where eager loading creates about 1M symbols, lazy loading
> reduces max RSS from 341 MiB to 154 MiB and time from 3.2 to 1.5
> seconds, with identical output.
> 
> Signed-off-by: Alireza Haghdoost <haghdoost@uber.com>

Sashiko has reviewed this patch and found no issues.

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Sashiko AI review · https://sashiko.dev/#/patchset/20261028-perf-symbol-memory-send-v6-0-7e90415f0101@uber.com?part=4